Furnace Repairs:
5 Tips to Troubleshoot your Unit

We're pleased to introduce Thompson Heating and Cooling, colleagues that provide HVAC services in the Louisville, Kentucky area. Here are a few tips from Fred Thompson.

 

(At Bornstein Sons, our northern and north central New Jersey heating clients often rely upon our annual tune-up services. Resourceful homeowners sometimes attempt to maintain their heating systems themselves. If you find your furnace in need of service and would like to check a few things, we're happy to share the following guest blog post.)

 

 

 

• Examine power connections to the furnace

Only after you have turned off the main power, remove the furnace’s main covering and make sure all of the wires are properly connected. Sometimes vibrations in the unit can loosen wiring on older units and cause its power source to become weakened or disconnected. While you are checking those connections, take a look at any fuses in the unit and make sure they are in good shape. A few words from Bornstein Sons: PLEASE NOTE: (This step is recommended ONLY for experienced professionals or well-informed hobbyists with a true understanding of electricity and dangers of mis-use. We strongly recommend engaging the services of a licensed insured professional heating contractor.) (FYI:  The reader should know that it is imperative that the door to your furnace be secured and closed properly. Failure to do this will cause the furnace to fail at start-up. See below.)

Repairing a furnace is as much about troubleshooting as it is about technical know-how. Many HVAC problems go unnoticed, sort of like the age-old analogy of placing a frog into a pot of lukewarm water and slowly increasing the temperature to a boil without the frog noticing there was ever a problem. The air conditioner and furnace in most people’s homes inconspicuously runs in the background, making them aware of HVAC problems only after the water has already reached its boiling point. By then, most of the damage has been done and the homeowner is left to contact an HVAC professional to get things back to normal.

Louisville heating repairs start to pick up in September and October as our local customers fire up their furnaces for the first time since the end of winter. A common scenario our team hears involves a phenomenon where a homeowner cannot get their furnace to stay on for longer than 4-5 hours. While this issue may require the trained hand of a licensed HVAC technician, there are a few things do-it-yourself homeowners can do to troubleshoot this problem:

•     Check the thermostat

        Sometimes furnace repair is as simple as changing the settings on your thermostat. Modern models of thermostats have so many options, comfort settings, speeds, and time schedules that it’s no wonder why some of us press the wrong button from time to time. Check the settings on your thermostat and make sure the fan is working properly. Then check to see if it is set to deactivate on a time schedule.

•     Examine power connections to the unit

        Only after you have turned off the main power, remove the furnace’s main covering and make sure all of the wires are properly connected. Sometimes vibrations in the unit can loosen wiring on older units and cause its power source to become weakened or disconnected. While you are checking those connections, take a look at any fuses in the unit and make sure they are in good shape.

•     Check the vent flue from the burner to the roof

        Depending on the type of unit in your home, the vent flue from the burner to the roof could become obstructed by bird nests and even large colonies of nesting spiders. This blockage could cause the unit to shut down unexpectedly. If you find obstructions, clear them and clean the vents. If you find that birds are getting into it from the roof, you might even consider attaching a screen to the opening to prevent any further tenancy.

•     Look for any evidence of charring or unusual burns

        Faulty wiring may also burn up the unit from the inside out. Many units have resistors and transistors on their boards; check those and make sure there isn’t any charring or evidence of burning. If there are major electrical problems with the unit, abort your do-it-yourself project and have it examined by a licensed technician.
   

An important word of advice: Make sure the door switch engages

        After all of the investigating, prodding, and troubleshooting wears you out, you may discover that the issue was even simpler than you could have ever imagined: it was the door switch! Most furnaces have a basic switch underneath the door covering that communicates to your unit that the door is closed and that it is okay to engage. If the door was not replaced properly, or it isn’t straight, the switch may engage and disengage with every vibration. If the door isn’t installed properly, it may not be engaging at all.

If none of these troubleshooting tips expose the problem, it is likely there are issues concerning the limit switch. Burners should remain lit throughout an entire cycle until the room reaches the selected temperature. In faulty units, the limit switch shuts down the burners prematurely. The limit switch also acts as a safety device that keeps the unit from having a possible meltdown. If this is the problem, it’s not a project you would want to tackle on your own.

Given the background function of home comfort units, many problems and needed repairs go unnoticed, even if a homeowner is consistently changing their air filters or using energy efficient models. If you happen to notice a change in your unit’s mechanics, remember to first check your thermostat for any accidental settings or operator-error. Then, shut off the breaker switch that feeds power to the furnace and check for loose wires, loose connections, bad fuses, and charred resistors and transistors. And last but not least, make sure the door switch is engaging properly. If none of these tips do the trick, contact your local HVAC technician to take a look at your unit and take care of any repairs that require advanced training and experience.

About the author: Kevin Thompson is the owner of Thompson Heating & Cooling based out of Louisville, KY. For all of your Louisville heating needs, contact Kevin.